Today there is a lot of breathing room between the top-performing 321-hp CTS 3.6-liter and the monstrous 556-hp CTS-V. Stepping into that power void for 2014 is a new twin-turbo 3.6-liter V-6. By “new,” we mean 90 percent of the parts are not shared with the naturally aspirated engine (basically everything but the front engine cover, cam drive, coil packs and a bunch of odds and ends). Rated in the CTS at 420 hp at 5750 rpm and 430 lb-ft at 3500 rpm (and those numbers are SAE certified), it produces 90 percent of peak torque from 2500-5500 rpm and ranks as GM’s most powerful V-6 ever. It even trumps BMW’s vaunted (and perhaps underrated) 3.0-liter I-6 turbo on power density (118 hp/liter versus 100 hp/liter).

Learn more about the 2014 Cadillac CTS' engine lineup here.As impressive as those stats are, assistant chief engineer Richard Bartlett is even prouder of the engine’s instantaneous throttle response and compact exterior size and low overall height, which allows it to fit in the ATS (we expect it to power the long-rumored ATS-V) and in the transverse XTS. (Fun fact about the transverse application: the same exact intake manifold is used, but it’s rotated 180 degrees. Output for the 2014 Cadillac XTS is 410 hp, 370 lb-ft.) Enabling both is a patented intake-manifold-mounted air-to-water intercooler system that dramatically shortens the path intake air must travel between the compressor and the intake valve, relative to the more typical air-to-air systems that must pump the charge out in front of the radiator and back. All that air acts like a big spring, but with 60 percent less air in the system, response is nearly instantaneous.

The two intercooling “bricks” look a lot like the ones atop the mighty LS9 supercharged V-8, cooled by a separate low-temperature cooling circuit capable of reducing the intake charge temperature from the 275 degrees it exits the compressor at, down to 113 (on a 75-degree day, at full power) — just as a typical air-to-air system does, and it does so with 80-percent efficiency at a cost of only 1 psi restriction. The twin turbos are fed by air split from a common air-cleaner and plenum, and the compressed air recombines to enter the engine via a single throttle body, so air compressed by the turbo on one bank could end up filling the cylinders of the other. Four resonators work to silence this complicated intake track, two upstream of the turbos and two between the turbos and intercoolers.The low-inertia, quick-spooling turbos use off-the-shelf housings from Mitsubishi Heavy Industries with custom internals and plumbing. They utilize vacuum-actuated, electronically controlled wastegates capable of dumping boost back to the turbo inlet whenever the driver snaps the throttle closed, so as not to waste the energy and be able to provide boost immediately if the driver toes back into the throttle. Peak boost is listed as “more than 12 psi.” Variable valve timing on both cams also helps improve response, by providing high overlap for “scavenging” that sends intake air rushing right out to speed up the spooling of the turbo. It also provides for internal EGR under other conditions.

The direct fuel injectors mount in the same place as those on the base 3.6 (and they’re isolated so as to minimize noise transmission), but the spray patterns from the six holes are uniquely suited to the greater degree of intake charge tumble and turbulence created by this engine’s unique (short) intake runners and machined domed pistons. The engine employs a virtual onboard weather station measuring humidity, temperature, and pressure before and after the turbos. All of this enables the relatively high 10.2:1 compression ratio that enables the engine’s high thermal efficiency.

Because some owners are expected to take their cars to track days, the lubrications system has been tested developed to keep the oil pickup tube submerged even under extreme g-loading conditions, as simulated by a test rig that can quickly rotate a running engine sideways or fore/aft to simulate 1g cornering or braking.Abetting the new engine will be an eight-speed paddle-shifted automatic transmission from Aisin Warner. The box expands the old six speed’s ratio spread (first-gear ratio divided by top-gear ratio) from 6.04 to 6.71. This enabled use of a taller axle ratio while still increasing torque multiplication by about 10 percent in first gear (for sprightlier sub-5-second acceleration) and lowering engine rpm by about 200 revs at 70 mph for a claimed 1.5-percent improvement in EPA highway fuel economy (official figures are not yet available, but figure upper-mid 20s on the highway in a Cadillac CTS). Consider this A-W transmission a stopgap measure until a home-grown GM unit becomes available in the near future.At this point we can only confirm that this will NOT be the next CTS-V engine (engineers become possessive of it when you ask about possible Corvette fitment), but we’ll be able to tell you more about Cadillac’s new twin-turbo V-6 after next week’s New York show introduction of the third-generation 2014 CTS.Source: Cadillac

Any idea why use this engine over the new lt1 i cant think of any excet ford has a ttv6 so should we ....gm said themselves using this enigine made less power heavier more expensive and worse mpg than the lt1 and offered no benefit so does that only apply to the vette and no other car

The Ford Ecoboost has been out for a while now. I'm sure there will be updates made to keep them ahead of the game. I would look for an announcement before this finds its way into the first car off the production line, since that seems to be how they have been doing things when it comes to annoucements from Chevy. The only question I would have regarding this engine is longevity. I know Ford did extremely extensive testing on the reliability of their ecoboost 3.5L, and they passed with flying colors. I will be curious to see how this does in comparison. I just wish Lincoln would get its act together and put out a decent car. Fwd 4 cyls are not going to cut it in a luxury division. One thing is for sure, there are going to be some really fast chevy's coming out across the board if they start throwing these in other models.

I remember GM people laughing at the "ecboost" idea not that long ago. I'm sure the same people will now be bragging (not that it isn't a bad motor to brag about) about how awesome twin-turbo V6's are.

If this makes it's way into the trucks, Ford better wake up. Then again, they knew it was to come and all they have to do is dial in more boost or change the timing curve and keep the waste gate closed longer.

Oh I'd say this motor will be popping up in a lot of GM cars in the future. Impressive numbers and specs, but I'd still take Fords eco-boost twin turbo...... Could this be the new engine in the new "base" Corvette? Yes, and I bet it will be. Heck, if they would put this in the newly redesigned Camaro in 2015, I'd buy one.....

I suspect this may be the power plant for the ATS-V and I wouldn't be surprised to see it under the hood of a performance version of the Alpha platform based 6th generation Camaro in a few years (and maybe even the C7 Corvette) after the new has worn off. I'd guess a CTS equipped with it might be best of the bunch, winning the Goldilocks award for being "just right". especially if Cadillac eventually offers a three pedal version of it.